Microwell plate

ABSTRACT

The shallower wells of a crystalisation plate in which it is intended to form crystals are part-spherical and of uniform wall thickness. The optical effect of the transparent plastics material from which the plate is moulded counter the distortion of a view through a microscope so that crystals viewed through the microscope appear to be on a flat surface. Associated with the wells are markings so small that they can be read through the microscope, making it unnecessary for the user to take the eye off the microscope to determine the position on the plate.

This Application is related to and claims priority from British PatentApplication No. GB 0513086,9 filed Jun. 28, 2005.

This invention relates to an improved microwell plate of the kind usedfor crystallisation, cell culture and general biological researchapplications.

BACKGROUND OF THE INVENTION

Such microwell plates are used for the investigative screening ofbiological samples. A plate has multiple formations each comprising arelatively deeper well and at least one relatively shallower well formedin a common depression in the top surface of the plate. A biologicalsample is placed in the shallower well and in the deeper well there isplaced a solution of chemicals designed to promote the growth ofcrystals in the shallower well by vapour deposition. As the solutionevaporates in some cases a crystal will form in the shallower well orwells from the vapour. The shallower wells are examined under amicroscope and when a crystal is found it is removed for analysis bypipette.

A principal object of the present invention is to provide an improvedmicrowell plate.

SUMMARY OF THE INVENTION

In accordance with the invention there is provided a microwell plate forcrystalisation, cell culture and general biological researchapplications comprising multiple formations each comprising a deeperwell and at least one transparent, relatively shallower well in an uppersurface of the plate, wherein the shallower well is of curved crosssection to be upwardly concave and generally uniform wall thickness.

Preferably the shallower well is part-spherical. The radius of curvatureof the sphere is preferably calculated equally with respect to its topand bottom surface to compensate for the refractive index of theplastics polymer used to manufacture the plate.

The wells of each formation are preferably within a common depression.The depth of said depression in the vicinity of the shallower well orwells is preferably in the region of not more than 800 microns.

Two similar relatively shallower wells may be associated with eachrelatively deeper well.

Preferably the formations are arranged in columns with lands separatingthe columns so that adhesive tape can be applied across parallel landson each side of a column to seal the formations therein.

The plate is preferably moulded from a transparent plastics material.

Individual indicia of dimensions such as to be viewed through amicroscope may be marked on the plate adjacent the shallower wells. Theindicia are preferably letters and/or numerals having a height in theregion of 0.8 mm and a width in the region of 0.1 mm.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the invention will now be described by way ofnon-limitative example with reference to the accompanying drawings, inwhich:

FIG. 1 is a plan view of a microwell plate in accordance with theinvention,

FIG. 2 is a sectional elevation taken on the line II-II of FIG. 1,

FIG. 3 is a view on an enlarged scale of one of the formations 3 of theplate of FIGS. 1 and 2, and

FIG. 4 is a sectional elevation taken on the line IV-IV of FIG. 3.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

The microwell plate 10 of FIGS. 1 and 2 is moulded from a transparentplastics material to have a flat upper surface 11 supported by aperipheral skirt 12. In the upper surface 11 multiple formations 3 areformed in columns separated by parallel lands 13. Each formation 3comprises a very shallow, generally rectangular depression 14 withinwhich a relatively deep well 15 is formed as well as two shallow wells16. As is most clear from FIG. 4 each shallow well 16 is of curved crosssection to be upwardly concave with a uniform wall thickness. When aspecimen in a shallow well 16 is inspected under a microscope it appearsflat, the curved appearance normal when viewing through a microscopehaving been countered by the optical properties of the plasticsmaterial. This is a surprising discovery. The “obvious” solution wouldbe to form the well 16 as a concave lens. Instead it is found that thedownwardly convex shape illustrated best serves this purpose andcompensates for the refractive index of the plastics polymer used in theconstruction of the plate.

In a preferred embodiment of the invention each depression is not morethan 800 microns in depth and the radius of curvature of eachpart-spherical shallow well 16 is in the region of 5 degrees.

With these dimensions it is relatively easy to pipette crystals out ofthe shallow wells 16. The lands 13 between the columns permit the wellsof all formations 3 of a common column to be sealed by a an adhesivetape (not shown) applied to parallel lands.

In accordance with another feature of the present invention uniqueindicia, such as letters and numerals 20,21 (FIG. 4) are marked in thedepression 14 of each formation between the deeper well 15 and theshallower wells 16. Each indices is so small as to be almost invisibleto the naked eye but can be read easily through a microscope. This meansthat an operator can identify the particular formation 3 he is lookingat without having to take his eye from the microscope. This greatlyaccelerates the examination process with consequent saving of theoperator's time. Preferably the indicia 20,21 are each no more than 0.8mm high and no more than 1 mm wide.

1. A microwell plate for crystalisation, cell culture and generalbiological research applications comprising multiple formations eachcomprising a deeper well and at least one transparent, relativelyshallower well in an upper surface of the plate, wherein the shallowerwell is of curved cross section to be upwardly concave and of generallyuniform wall thickness.
 2. A plate as claimed in claim 1, wherein theshallower well is part-spherical.
 3. A plate as claimed in claim 2,wherein the radius of curvature of the sphere is in the region of 5degrees.
 4. A plate as claimed in claim 1, wherein the wells of eachformation are within a common depression in the upper surface of theplate.
 5. A plate as claimed in claim 4, wherein the depth of each saiddepression in the vicinity of the shallower well or wells is in theregion of not more than 800 microns.
 6. A plate as claimed in claim 1,wherein two similar relatively shallower wells are associated with eachrelatively deeper well.
 7. A plate as claimed in claim 1, wherein theformations are arranged in columns with lands separating the columns sothat adhesive tape can be applied across parallel lands on each side ofa column to seal the formations therein.
 8. A plate as claimed in claim1 moulded from a transparent plastics material.
 9. A plate as claimed inclaim 1, wherein individual indicia of dimensions such as to be viewedthrough a microscope are marked on the plate adjacent the shallowerwells.
 10. A plate as claimed in claim 9 wherein the indicia are lettersand/or numerals having a height in the region of 0.8 mm and a width inthe region of 0.1 mm.